Isoindoles



United States Patent Oflice 3,084,167 Patented Apr. 2, 1963 3,084,167 ISOINDOLES Leonard M. Rice, Baltimore, Md., assignor to The Gesehickter Fund for Medical Research, Inc., Washington, D.C., a corporation of New York No Drawing. Filed Dec. 9, 1954, Scr. No. 474,288 9 Claims. (Cl. 260-319) The present invention relates to organic compounds, particularly new, substituted isoindole derivatives and their quaternary salts with various hydrogenation states and to methods of producing such compounds.

According to the present invention, generally stated, new products which are of outstanding value in the treatment of various diseases are made by preparing N-substituted isoindoles, of varying degrees of hydrogenation of the type represented by the formula and conversion to their corresponding di-methionium salts, having the formula:

Also, in the general formulae,

N R V represents (1) a dialkylamlno group or radical having from 1 to 6 carbon atoms in the alkyl chains or (2) a heterocyclic alkylamino group or ring such as morpholine, pyrrolidine or piperidine; n represents a number from 2 to 6 and x represents a halogen ion such as chloride, bromide or iodide or the methylsulfate ion.

At this juncture, it is pointed out that the naming of these compounds is in conformity with the Patterson Ring Index as illustrated in the following examples in which numbers 8 and 9 had to be assigned to the two carbon atoms at the ring junctions.

Octahydrolsoindole Isotdoline or dihydroisolndollne The products of the present invention may be prepared by reacting a dialkylaminoalkylamine or heterocyclicalkylamine with a molecular equivalent of the corresponding acid anhydride. The acid anhydrides used in this invention are phthalic; tetrahydrophathalic; endomethyleno tetrahydrophthalic; 5 methyl tetrahydrophthalic; 3,5-dirnethyl tetrahydrophthalic; endomethylene hexahydrophthalic; S-methyl hexahydrophthalic; 3,5- dimethyl hexahydrophthalic; 3-methy1 tetrahydrophthalic; and 3-methyl hexahydrophthalic; as well as those derived from hexahydrophthalic, anhydride, dichlorophthalic anhydride, and tetrachlorophthalic anhydride and halogen substituted derivatives such as by chlorine, bromine, and iodine and the hydrogenated derivatives of these phthalic anhydrides.

The resulting N-substituted dialkylaminoalkyl imide is then reduced by suitable means, for example, with lithium aluminum hydride or sodium in alcohol, or catalytically or electrolytically, to the corresponding isoindole derivative which is then methylated to the quaternary salt. The following examples illustrate this synthesizing process of the present invention and exemplary compounds resulting therefrom. These examples are to be construed as merely illustrative and not limiting the scope of the present invention.

EXAMPLE I N-Diethylaminoethyl Octahydroisoindole- Dimethyl Quaternary Iodide A mixture of 116 grams (1 mole) of diethylaminoethylamine and 154 grams (1 mole) of hexahydrophthalic anhydride was heated in a bath at 160-170 C. for 4 hours. The mixture was allowed to cool and then vacuum distilled. The distillation yielded 220 grams of N-diethylaminoethyl hexahy-drophthalimide boiling at 132-135 C. at 2 mm. pressure.

With stirring 110 grams of the N-diethylaminoethyl hexahydrophthalimide was added dropwise to 36 grams of lithium aluminum hydride dissolved in 1000 ml. of anhydrous ether at such a rate as to maintain a gentle reflux of the ether. After all the material was added, the reaction mixture was decomposed with a minimum amount of cold water. This was determined by the liberation of hydrogen and refluxing of the other. When gas was no longer evolved, the mixture was stirred for 25 hours and then filtered. The ethereal filtrate was concentrated to give the isoindole derivative which, when distilled at a pressure of 2 mm., boiled at 93-96 C. and weighed grams.

The isoindole derivative was dissolved in absolute alcohol and treated with a 10% excess of methyl iodide. The quaternary salt crystallized out of the solution and after recrystallization from alcohol melted at 224- 225 C.

EXAMPLE II 1 0 a N 2 5 l C H CH A mixture of 116 grams of diethylaminoethyl amine and 152 grams of cis-A tetrahydrophthalic anhydride was maintained at 160-170 C. for 4 hours. After cooling, the mixture was vacuum distilled whereupon it yielded 210 grams of N-diethylaminoethyl cis A tetrahydrophthalimide boiling at 132-134 C. at 2 mm.

110 grams of the above imide was added, at such a rate as to just maintain reflux, to 36 grams of lithium aluminum hydride dissolved in 1000 ml. of anhydrous ether. When all the material had been added, the reaction mixture was decomposed with a minimum amount of cold water. The solution was filtered and the filstanding. After recrystallization from alcohol the quaternary salt of the isoindoline melted at 218-220 C.

The isoindoline derivative was dissolved in absolute alcohol and treated with a 10% excess of methyl iodide. The quaternary salt precipitated from the solution on standing. After recrystallization from alcohol the quaternary salt of the isoindoline melted at 218-220 C.

EXAMPLE III N-Diethylaminoethyl-I-3-Dihydroisoindole Dimethiodide 011, CH; 02H l I+-GiH N+ A mixture of 116 grams of diethylaminoethylamine and 148 grams of phthalic anhydride was heated at 160- 170 C. for 4 hours. When cool, the mixture was vacuum distilled and yielded 215 grams of N-diethylarninoethyl phthalirnide boiling at 140-143 C. at 2 mm.

With stirring, 110 grams of the above imide was added, at such a rate as just to maintain reflux, to 36 grams of lithium aluminum hydride dissolved in 1000 ml. of dry ether. When all the imide was added the reaction mixture was decomposed with a minimum amount of cold water. The solution was filtered and the filtrate was concentrated to give the isoindole which, when distilled at a pressure of 2 mm., boiled at 101- 104 C.

The isoindole derivative was dissolved in absolute a1- cohol and a 10% molar excess of methyl iodide was added. The product which separated after recrystallization from alcohol melted at 193-194 C.

EXAMPLE IV N-Diethylaminoethyl-4,7,8,9-Tetrahydr-4,7- Endomethano-Isoindoline Dimethiodide The imide may be prepared by reacting 116 grams of diethylaminoethylamine with 164 grams of 3,6-endomethylene-cis-M-tetrahydrophthalic anhydride as in Example I. This imide boils at 142144 C. at 2 mm. pressure.

Reduction of the imide as in Example I yielded 109 grams of the isoindoline direvative boiling at 122-124 at 2 mm. pressure.

Conversion into the methionium salt as in Example I yielded the quaternary salt melting at ZOE-210 C.

4 EXAMPLE v N-Dimethylamin0ethyl-6-Methyl-4,7,8,9-

Tetrahydroisoindoline Dinzethiodide The imide was prepared from S-methyl cis-A -tetrahydrophthalic anhydride as in Example I and boiled at 106-112 C. at 0.2 mm.

Reduction by means of lithium aluminum hydride as in Example I yielded the base boiling at 7885 C. at 0.1 mm.

Conversion to the quaternary salt as in Example I gave the product which, after recrystallization, melted at 203205 C.

EXAMPLE VI N-Dimethylaminoethyl-4,6-Dimethyl-4,7,8,9-

Tetrahydroisoindoline Dimelhiodide The imide was prepared from 3,5-dimethyl cis-M- tetrahydrophthalic anhydride as in Example I and boiled at 101105 C. at 0.1 mm. The base was obtained by reduction as in Example I and boiled at 87-94 C. at 0.1 mm. Conversion to the dimethiodide as in Example I yielded the salt with a melting point of 194-197 C.

EXAMPLE VII N-Dialky lamin0alkyl-4,5 ,6 ,7,8,9-H exahy dro-4,7- Endomethano lsoindolines A. These isoindolines and their derivatives were prepared in the manner illustrated by the foregoing examples, the starting anhydride being endomethylene hexahydrophthalic anhydride which recently has become cornmercially available. The imide resulting when this anhydride is reacted with diethylaminoethyl amine is N-diethylaminoethyl endomethylene hexahydrophthalimide, which has a boiling point of 130135 C. at 2 mm. pressure. The hydrochloride salt of this imide has a melting point of 205206 C. Reduction of the imide gives the corresponding isoindoline having a boiling point of -114 C. at 1 mm. The dimethiodide, obtained by methylation of this isoindoline as hereinbefore described, has a melting point of 213214 C.

B. With the same anhydride and dimethylaminoethyl amine, the corresponding compounds were obtained and are characterized as follows:

Imide: N dimethylaminoethyl-endomethylene hexahydrophthalimide, boiling point, -123 at 2 mm.

Imide hydrochloride: Melting point, 201-203 C.

Isoindoline: N-dimethylaminoethyl-4,5,6,7,8,9-hexahydro- 4,7-cndomethano-isoindoline, boiling point, 103408 C. at 2 mm.

lsoindoline dirncthiodide: Melting point, 220--221 C.

The following tabulation presents further examples of compounds embraced by the invention, which were prepared according to the procedure set forth hereinabove.

TABLE II-Continued N-DIALKYLAMINOALKYLISOINDOLINES Analysis, percent Dimcthiodide B.P., 1101 T i R Formula C. Mn. Carbon Hydrogen Nitrogen Ml., Nitrogen C M.P.,

C. Calcd. Found Calcd. Found Calcd. Found Galcd. Found Diothylamincethyl CnllnNz 101 104 2 77.01 76. 87 10. 15 9. 76 12. 83 12. 54 234-235 193-194 5. 58 5. 5] DirnethylaminopropyL. cmllmNfl 120-123 3 70. 42 76. 12 .1. B7 0. 40 13. 71 13. -11 246 247 237-238 5. T4 .5. 88 blowliolinopropyl C IHQN OUH 1li4l08 3 T3. l3 T2. 97 9. U 8. 70 ll. 37 11.57 247*248 230*231 5. 2 5. 2i)

N'DIA LRYLA MINOALKYL OCTAILYDROISOINDO LES Dirnolllylanlinoetllyl 77 30 2 T3. 41 73.10 12.32 l2. 19 14.27 14.02 276078 5. S3 5. 88 Dicthylaminnethyl C 93 .16 2 74. 33 75. (ll 12.55 12.21 14.43 12. 23 177478 5. 5i 5. 24 Dimctllylatnlnoi roj y]. H5 85 2 74. 22 74.10 12.40 12. .10 13.32 0. 08 5. 71 Dietllyluminot roilylr 105*107 2 74. 5t) 4. 9i) l2. 6?? 12.30 11.75 5. 30 56 1\lor} l10lin0cth v]r 1474 19 5 70. 54 70. 11 10.99 10.63 11.75 I 7. 3R T. 40 1M1orpl1olinopmpy 132*135 2 71.38 71. 24 11. 18 10. 93 ll. 10 5. 27 5. 3S Dibutylanilnoproliy llfi lll 0. 1 77. -18 77, $1 13. 01 12. 81 U. 51 4.1% 5. O1 Dihoxylarninoethylfl 140445 0. l 78. 50 77. 05 13. l8 13. 23 8. 32 4. 52 4. 4S Dlethylamlnohoxyl. 110 120 (1.1 77. [)7 76. 99 12. 92 12.03 9. 00 4. 0|) 5. (l2 Piperdinoethyl 103*10? l. l 70. 76.29 11.94 11.69 11.85 5. 3S 5. 32 Diethylnrnlnobutyl 83 87 0. 02 76. 12 76.50 12. 78 12. 64 11. 10 47. 33 4G. 98 3dlcthylaminopropanal-2 105*115 0. l 70. 81 71. 11. 89 11. 96 11.01 47. 15 10. 89

1 Monomethiodide.

N-DIALKYLAMINOALKYL-B-METHYLAJ .8 .Q-TETRAHYDROISOINDOLINE Dimethylaminoethyl. C 13 I71Nu 78 85 0. 1 74. 94 74. 65 11.61 11. 38 13. 45 13. 48 262-263 203-205 5. 69 5. 58

Following the same general procedure, the trimethoniurn salt of isoindole has been prepared having the following formula:

Calculated Found Carbon 52. 75 52. 84 7. 47 7. 77 11. 53 11. 26 Chlorine 19. 19. 41

The isoindole base obtained as described above had a boiling point of 136 to 142 C. at 0.1 mm. and gave the following analytical figures:

k Calculated Found Carbon 72. 95 72. 90 Hydrogen--. 11.10 10. 88 Nitrogen 15. 95 16.21

The trihydrochloride had a melting point of 270 to 271 C. and analyzed for 28.54% chlorine, the theoretical amount being 28.53%. The trimethonium compound obtained as above employing methyl iodide, melted at 213 to 215 C. and analyzed 54.94% iodine, the theoretical amount being 55.24%.

The compounds bis-methionium salts of the present invention have proven especially effective in the treatment of hypertension and are superior to any presently known remedies.

There are two compounds being presently used in the treatment of hypertension, known under the proprietory names of Bistrium" and Apresoline, and these compounds have been only recently introduced. These drugs have certain definite disadvantages. Both drugs have a rather severe, rapid action which may result in fainting on standing (postural hypotension) and the action is relatively brief, being from about 3 to 20 hours. Bistrium and Apresoline also, in certain cases, exhibit side reactions such as headache, palpitation, nausea and fainting, and Apresoline apparently has a damaging effect on the blood and bone marrow when given over a long period of time which has, in some cases, been fatal. The effect of Bistrium or Apresoline on the blood pressure is unpredictable and overdoses can reduce blood pressure to shock or coma levels. In some cases the blood pressure may even drop to zero.

The isoindoles of the present invention have a slower and more prolonged or sustained effect in lowering blood pressure and seem to have a saturation or plateau efiect so that overdosage is not serious. Even if an overdose is administered, the blood pressure is not reduced to shock or coma levels. None of the side reactions of Bistrium and Apresoline have been observed with the use of isoindoles and the isoindoles seem to have a relaxing effect on nervous as well as hypertensive individuals. The effect of these isoindoles lasts 48 hours or more in observed cases.

The compound may be administered intramuscularly or orally. Doses of 10 to 30 mg. in sterile aqueous solution may be given intramuscularly every other day and mg. tablets may be given once daily. Such dosages are sufficient to reduce and hold blood pressure at safe levels and no toxic or unpleasant side effects have been observed.

The present application is a continuation-in-part of my application Serial No. 336,457, filed February 11, 1953, now abandoned.

From the foregoing it will be apparent that I attained the object of my invention and have provided new and useful compounds for the treatment of hypertension.

I claim:

1. A compound selected from the group consisting of (l) N-substituted isoindoles of the formula A N HI) n-N R wherein ring A is selected from the group consisting of phenyl; cyclohexene; endomethylene cyclohexene; 3- methyl cyclohexene; S-methyl cyclohexene; 3,5-dirnethyl cyclohexene; cyclohexane; 3-methyl cyclohexane; 5- methyl cyclohexane; 3,5-dimethyl cyclohexane; endomethylene cyclohexane; 6-1nethyl cyclohexene; 6-rnethyl cyclohexane; 4 methyl cyclohexene; 4-methyl cyclohexane; 4,6dimethyl cyclohexene; 4,6dimethyl cyclohexane; wherein n is a whole number from 2 to 6; and wherein A N R V is an amino group selected from the group consisting of morpholine, piperidine, pyrrolidine and dialkylamine of from 1 to 6 carbon atoms in the alkyl chain; and (2) the therapeutically useful dimethonium salts thereof.

2. The compound N-dimethylaminoethyl dihydroisoindoline.

3. The compound N-dimethylaminoethyl tetrahydroisoindoline.

4. The compound N-dimethylaminoethyl hexahydroisoindoline.

5. The compound N-dimethylaminoethyl endomethanoisoindoline.

References Cited in the file of this patent UNITED STATES PATENTS 2,143,751 Adkins Jan. 10, 1939 2,432,905 Kharasch et al Dec 19, 1947 2,528,940 Wright Nov. 7, 1950 2,541,211 Cusic Feb. 13, 1951 2,807,624 Grogan et a1. Sept. 24, 1957 FOREIGN PATENTS 987,158 France Apr. 11, 1951 OTHER REFERENCES Jour. Am. Chem. Soc., vol. 68, pp. 1657-58 (1946). Comptes Rendus, vol. 222, pp. 1443-44 (1946). Chem. Abstracts, vol. 45, pp. 5146 and 9527 (1951). Beilstein, 4th ed., vol. XX, 2nd supp, page 172 (1953). 

1. A COMPOUND SELECTED FROM THE GROUP CONSISTING OF (1) N-SUBSTITUTED ISOINDOLES OF THE FORMULA
 2. THE COMPOUND N-DIMETHYLAMINOETHYL DIHYDROISOINDOLINE. 